WORCESTER — A North Brookfield police officer was sentenced to 3 ½ years in jail Thursday after admitting in court that he sexually assaulted a 15-year-old girl and sent an obscene photo to the victim's cellphone.

Adam J. Kachadoorian, 44, pleaded guilty in Worcester Superior Court to charges of child rape, indecent assault and battery on a person 14 or older, distribution of obscene matter and dissemination of matter harmful to a minor. A charge of child rape aggravated by age difference was dismissed as part of a plea agreement in the case.

As recommended by Special Prosecutor Michael V. Caplette and Officer Kachadoorian's lawyer, Timothy M. Burke, Judge James R. Lemire sentenced him to 2 ½ years in the House of Correction on the indecent assault and battery charge and to a consecutive sentence of 2 ½ years in the House of Correction, with one year to be served, on the distribution and dissemination charges.

The balance of the latter sentence was suspended for 5 years with probation.

Mr. Caplette said the sexual assaults occurred Oct. 13, 2011, at the victim's Leicester home. The 15-year-old and her family told police Officer Kachadoorian also sent a photo of male genitalia to the girl's cellphone, texted her to ask if she was going to tell her parents and, after being confronted, said he had engaged in consensual sex with the teen, according to the special prosecutor.

Before the start of the plea hearing, Mr. Caplette asked Judge Lemire to close the courtroom to the public because of the victim's age. The judge denied the request.

A full-time patrolman in North Brookfield since 2004, Officer Kachadoorian was placed on administrative leave after being charged. He was also ordered by the court to surrender all of his weapons as a condition of his release on $1,000 cash bail.

In an impact statement read by Jennie L. Caissie, also a special prosecutor in the case, the victim spoke of the "psychological distress" that she experienced as a result of Officer Kachadoorian's actions.

"It took me awhile to get over the fact that it wasn't my fault. I was a minor and he was a grown man," she said in her statement.

Mr. Burke described his client's crimes as "an aberration" and told the court Officer Kachadoorian was "extremely remorseful for his conduct."

Conditions of probation imposed by Judge Lemire included sex-offender registration, a sex-offender evaluation and any related counseling deemed appropriate and GPS monitoring. Officer Kachadoorian was further ordered to have no contact with the victim.

Mr. Caplette also asked that the officer be required to pay restitution as a condition of probation for out-of-pocket expenses incurred by the victim and her family in connection with the case. A hearing to determine the amount of restitution to be paid was scheduled for Oct. 21.